Characterization of multiphase gas–solid flow and accuracy of turbulence models for lower stage cyclones used in suspension preheaters

This study involved the analysis and characterization of the multiphase flow phenomenon inside the lower stage cyclone separator used in the clinker burning process. The analysis was performed using both CFD and experimental research methods. Very few studies are devoted to such types of cyclone separators, which in addition to their basic functions are also responsible for the technological process. Due to the atypical working conditions of these cyclone separators, they are characterized with a complex geometry, which significantly differs from that of the traditional separators.Furthermore, the evaluation of the accuracy and level of reliability of the two models of turbulence closure—k-e RNG and RSM(RANS), and the LES. The results obtained led to the conclusion that for the lower stage cyclone separators, the LES model proved to be the most accurate(both in the case of forecasting the separation efficiency and pressure drop). The performance parameter(in particular the separation efficiency) values obtained for the RSM model were also characterized by high accuracy. The k-e RNG model was characterized by significantly larger deviations.     

Application of Computational Methods for the Design of BACE-1 Inhibitors: Validation of in Silico Modelling

β-Secretase (BACE-1) constitutes an important target for search of anti-Alzheimer’s drugs. The first inhibitors of this enzyme were peptidic compounds with high molecular weight and low bioavailability. Therefore, the search for new efficient non-peptidic inhibitors has been undertaken by many scientific groups. We started our work from the development of in silico methodology for the design of novel BACE-1 ligands. It was validated on the basis of crystal structures of complexes with inhibitors, redocking, cross-docking and training/test sets of reference ligands. The presented procedure of assessment of the novel compounds as β-secretase inhibitors could be widely used in the design process.     

THERMOELECTRIC CHARACTERISTICS OF MICROSCALE THIN-FILM THERMOCOUPLES

Microscale thin-film thermocouples (TFTCs), which can be fabricated using existing microelectronics technology on the surfaces of electronic de vices with film thicknesses as small as tens of angstroms, ha ve smaller thermoelectric potential compared to thick-film cases. The qualititati ve characteristics of TFTCs, which ha ve not yet been modeled successfully, ha ve been analyzed based on the model of distributed electric potential across the interface of two metals. The steady-state solution of the electron distribution and the electric potential distribution by solving the one-dimensional Schrodinger equation and the Poisson equation simultaneously show the decrease in the thermoeleectric potential quantitatively.     

Dual-pulse laser-induced breakdown spectroscopy in bulk aqueous solution with an orthogonal beam geometry

Use of dual-pulse laser-induced breakdown spectroscopy with an orthogonal spark orientation is presented as a technique for trace metal analysis in bulk aqueous solutions. Two separate Q-switched Nd:YAG lasers operating at their fundamental wavelengths are used to form a subsurface, laser-induced plasma in a bulk aqueous solution that is spectroscopically analyzed for the in situ detection of Ca, Cr, and Zn. Optimizing the key experimental parameters of proper spark alignment, gate delay (td), gate width (tb), and interpulse timing (deltaT) allowed experimentally determined detection limits of the order of micrograms per milliliter and submicrograms per milliliter. We present supporting evidence of a sampling mechanism that involves the formation of a cavitation bubble with the first pulse (E1) followed by analysis of that bubble with a second pulse (E2). The plasma created by E2 contains the analytically relevant information from the aqueous sample and often represents >250-fold enhancement over a single laser pulse with energy equal to E1 alone.     

Growth, structure, and morphology of TiO2 films deposited by molecular beam epitaxy in pure ozone ambients

TiO₂ films were grown using a reactive molecular beam epitaxy system equipped with high-temperature effusion cells as sources for Ti and an ozone distillation system as a source for O. The growth mode, characterized in-situ by reflection high-energy electron diffraction (RHEED), as well as the phase assemblage, structural quality, and surface morphology, characterized ex-situ by X-ray diffraction and atomic force microscopy (AFM), depended on the choice of substrate, growth temperature, and ozone flux. Films deposited on (1 0 0) surfaces of SrTiO₃, (La_0.27Sr_0.73)(Al_0.65Ta_0.35)O₃, and LaAlO₃ grew as (0 0 1)-oriented anatase. Both RHEED and AFM indicated that smoother surfaces were observed for those grown at higher ozone fluxes. Moreover, while RHEED patterns indicated that anatase films grown at higher temperatures were smoother, AFM images showed presence of large inclusions in these films.     

Flexible hydrogen gas sensor based on a capacitor-like Pt/TiO2/Pt structure on polyimide foil

Metal oxide semiconductor gas sensors of hydrogen with a typical capacitor-like Pt/TiO₂/Pt electrode arrangement exhibit excellent sensitivity to hydrogen even at room temperature. At the same time, very similar Pt/TiO₂/Pt cells can also be used as memristive elements exhibiting resistive switching between two resistive states, which has been recently exploited to create a gas sensor with built-in memory. Merging of these two functionalities within a single device also opens new possibilities for smart gas sensor arrays. However, so far such sensors have been prepared only on rigid substrates. In this work, a flexible hydrogen gas sensor with such capacitor-like Pt/TiO₂/Pt electrode arrangement fabricated on polyimide foil is presented and characterized in terms of hydrogen gas sensing properties and bending endurance. The sensor exhibits high response (R_air/R_H2) of more than 10⁵ to 10 000 ppm H₂ at 150 °C with minor decline at elevated humidity and is capable of room temperature operation. The lowest detected concentration was 3 ppm at 150 °C and 300 ppm at room temperature in dry conditions. Bending the sensor 10⁵ times over diameter of 10 mm led to slight improvement of the sensing performance.     

Similarity and generalized analysis of efficiencies of thermal energy storage systems

This paper examined the features of three typical thermal storage systems including: 1) direct storage of heat transfer fluid in containers, 2) storage of thermal energy in a packed bed of solid filler material, with energy being carried in/out by a flowing heat transfer fluid which directly contacts the packed bed, and 3) a system in which heat transfer fluid flows through tubes that are imbedded into a thermal storage material which may be solid, liquid, or a mixture of the two. The similarity of the three types of thermal storage systems was discussed, and generalized energy storage governing equations were introduced in both dimensional and dimensionless forms. The temperatures of the heat transfer fluid during energy charge and discharge processes and the overall energy storage efficiencies were studied through solution of the energy storage governing equations. Finally, provided in the paper are a series of generalized charts bearing curves for energy storage effectiveness against four dimensionless parameters grouped up from many of the thermal storage system properties including dimensions, fluid and thermal storage material properties, as well as the operational conditions including mass flow rate of the fluid, and the ratio of energy charge and discharge time periods. Engineers can conveniently look up the charts to design and calibrate the size of thermal storage tanks and operational conditions without doing complicated individual modeling and computations. It is expected that the charts will serve as standard tools for thermal storage system design and calibration.     

Innovation Systems in Tourism: The Roles of Attractors and Scene-Takers

This paper proposes a model of an attractor-based innovation system for understanding tourism. Key components of the model are the attractor (that which attracts visitors), scene-maker, scene, collaborative networks between tourism and other firms and, finally, the crucial function of the scene-taker. Findings from eight in-depth case studies taken from around the world are summarized in the form of seven hypotheses concerning the operations of such innovation systems. It is argued that scene-takers, in the form of individual entrepreneurs and organizations, perform a crucial function in the innovation system in developing and maintaining the scene. Finally, some policy implications for building such a system are suggested.     

A comparative study between intermittent microwave and infrared drying of bioproducts

A systematic experimental study of both intermittent microwave (MW) and infrared (IR) drying was used to compare the efficacy of the two methods when batch drying two bioproducts, namely potato and carrot. The controllable parameters examined in this study were MW power and IR intensity level, MW and IR intermittencies and the transition period from convective to MW drying. A comparison of the drying kinetics showed intermittent MW drying to be an effective method for shortening the drying time that was required to reach a certain moisture content when it was compared with intermittent IR drying and convective‐MW drying. A comparison of the colour degradation of the product showed that step variation of the IR intensity during intermittent drying reduced the colour change of the product less than constant radiative intermittent IR drying.     

Composing software services in the pervasive computing environment: Languages or APIs?

The pervasive computing environment will be composed of heterogeneous services. In this work, we have explored how a domain specific language for service composition can be implemented to capture the common design patterns for service composition, yet still retain a comparable performance to other systems written in mainstream languages such as Java. In particular, we have proposed the use of the method delegation design pattern, the resolution of service bindings through the use of dynamically adjustable characteristics and the late binding of services as key features in simplifying the service composition task. These are realised through the Scooby language, and the approach is compared to the use of APIs to define adaptable services.